Dobby for looms

ABSTRACT

A dobby for looms of the type in which an arrangement of actuating members or amplifier relays which is interposed between a reading device and pulling levers is controlled by a common shaft to which in use a cyclic rotary motion is imparted. Each member comprises a profiled cam loosely mounted on the common shaft and provided with a sliding cotter. During periods in which the common shaft is stopped, the cotter can be displaced by either one of two pivoting fingers which are controlled by the reading device. The control is such as to ensure that either the shaft and cam are prevented from rotating relative to each other, or the cam cannot be moved. A moving part is provided which supports a roller held in contact with the periphery of the cam, the moving part being attached to the corresponding pulling lever.

United States Patent [191 Amigues DOBBY FOR LOOMS [76] Inventor: Lucien Amigues, 25, avenue Gabriel Peri, Vincennes, France [22] Filed: Nov. 14, 1972 [21] Appl. No.: 306,187

[52] 11.8. CI 139/66 R [51] Int. Cl. D03c 1/00 [58] Field of Search 139/66 R-74 [56] References Cited UNITED STATES PATENTS 1,256,644 2/1918v Barlow 139/66 R 3,180,366 4/1965 Hoenig.... 139/66 R 3,468,347 9/1969 Fumat 139/66 R 3,724,510 4/1973 Kleincr.... 139/66 R 3,730,231 5/1973 Hoenig 139/66 R FOREIGN PATENTS OR APPLICATIONS 258,377 4/1913 Germany 139/66 R 1,201,358 7/1959 France 139/66 R 1,405,184 5/1965 Francem", 139/66 R Primary Examiner--James Kee Chi Attorney, Agent, or Firm-Alexander & Dowell 5 7] ABSTRACT A dobby for looms of the type in which an arrange ment of actuating members or amplifier relays which is interposed between a reading device and pulling levers is controlled by a common shaft to which in use a cyclic rotary motion is imparted. Each member comprises a profiled cam loosely mounted on the common shaft and provided with a sliding cotter. During periods in which the common shaft is stopped, the cotter can be displaced by either one of two pivoting fingers which are controlled by the reading device. The control is such as to ensure that either the shaft and cam are prevented from rotating relative to each other, or the cam cannot be moved. A moving part is provided which supports a roller held in contact with the periphery of the cam, the moving part being attached to the corresponding pulling lever.

5 Claims, 10 Drawing Figures DOBBY FOR LOOMS The present invention relates to dobbies for looms.

Dobbies have been proposed in which the actuating members or amplifier relays interposed between the customary reading device and the pulling levers associated with the frames or healds comprise connecting rods actuated by eccentrics supported by a common shaft rotated in cyclic manner rather than balances controlled by moving crosspieces. Such dobbies have been proposed with a view to simplifying construction by decreasing the number of moving parts and to increasing the operating speed. In constructions of this type the head of each connecting rod is loosely mounted-on the corresponding eccentric and a locking mechanism is provided which is connected to the reading device. This mechanism, which is of a relatively complex construction, permits the eccentric to be driven by the shaft.

Tests have shown that dobbies of this type, sometimes known by the name of rotary dobbies, do not produce all the results expected. In the first place, it will be understood that each drive member comprises two anti-friction bearings (the first interposed between the shaft and the eccentric, the second between the eccentric and the head of the connecting rod) one of which has a relatively large diameter and is subjected to very severe operating stresses which may cause rapid wear and tear. The replacement of this bearing necessarily involves replacing the complete connecting rod.

'Moreover, the locking mechanism is complicated,

which increases the risks of damage and the frequency of repairs. It should be noted that the replacement of one part necessitates the dismantling of all the actuating members of the dobby. It should also be noted that the arrangement has reduced reliability, despite relatively high construction and maintenance costs. Finally and above all a system having a eccentric and connect ing rod naturally has a law of inalterable movement, which it is thus impossible to modify when necessary.

The improvements which are the object of the present invention relate specifically to facilitating the construction of a dobby of the rotary type which does not have the aforesaid drawbacks and which is thus able to fulfil the various requirements of the art particularly well.

According to the present invention, there. is provided a dobby for looms of the type in which an arrangement. of actuating members or amplifier relays which is interposed between a reading device andpulling levers is controlled by a common shaft to which in use a cyclic rotary motion is imparted, wherein each member comprises, a profiled cam loosely mounted on the common shaft and provided with a sliding cotter which, when the shaft is stopped, can bedisplaced by either one of two pivoting fingers which are controlled by the reading device to ensure either that the shaft and cam are prevented from rotating relative to each other or that the cam cannot be moved, a moving part being provided which supports a roller in contact with the periphery of the aforesaid cam and which is attached to the corresponding pulling lever.

The sliding cotter is preferably mounted inside a radial housing in the cam and is biased by resilient means, for example springs towards the common shaft in such a manner that its end engages in one or the other of two opposed notches provided in the edge of a ring keyed on said shaft. Each of the pivoting fingers comprises a terminal nose engaged in a groove provided in one of the cam faces, said nose being shaped in order to control the cotter longitudinally with a view to urging it outwards against the action of the resilient means associated therewith, or to releasing it to facilitate its engagement in either of the two aforementioned notches.

It will be understood that all of this control mechanism may be housed laterally with respect to the cam, thus providing towards the bottom a free space for mounting the moving part provided with the roller.

This moving part may comprise a single pivoting arm 1 appropriately attached to the pulling lever, in the case where it is desired to produce a dobby of the negative type in which the return of the frames or healds is produced by springs or other spring means. On the other hand, when dealing with a positive dobby, the moving part advantageously comprises a cradle provided with two opposed rollers and suspended from two connecting rods in order to be able to be displaced laterally under the effect of the rotation of the cam. One of said connecting rods can comprise an extension of the pivoted pulling lever. I

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings; in which:

, FIG. 1 is a cross-section showing'one of the actuating members of a positive dobby constructed according to the invention. I

FIG. 2 is the same view as FIG. 1 after the longitudinal control shaft has been displaced through FIG. 3 shows in perspective, prior to their assembly, the cam of the member of FIGS. 1 and 2 and the parts associated therewith.

FIGS. 4 and 5 are cross-sections to a larger scale illustrating the operation of the cotter.

FIGS. 6 and 7 are partial longitudinal sections, on lines VIVI and VIIVII (FIG. 1) respectively.

' FIGS. 8 to 10 illustrate various applicationsof the invention.

Referring to FIGS. 1 and 2, the reference numeral 1 designates a common longitudinal control shaft of the dobby. Associated with this shaft 1 is a drive mechanism (not shown) capable of imparting thereto a cyclic rotary motion such that it is displaced angularly through 180 between two consecutive stoppages. The shaft 1 carries a series of appropriately profiled cams 2 (FIG. 3). Interposed between the central aperture of each cam 2 and the periphery of the shaft 1 is a bearing 3 of the ball-bearing, anti-friction bearing or roller bearing type.

As shown in FIG. 3, two concentric grooves 2a and 2b are provided in one of the faces of each cam 2. The inner groove 2a is intended to form a housing for the edge of a dished ring 4, which is held against angular movement with respect to the shaft 1 by means of a radial tongue 4a which engages a longitudinal groove 1a (FIGS. 4 and 5) in said shaft. Two diametrically opposed notches 4b are provided in the edge and the periphery of the ring 4.

Thegrooves 2a and' 2b in the cam 2 are broken by an aperture 2c which forms a housing for a cotter S mounted so as to slide radially in said aperture. Two return springs 6 are associated with this-cotter 5, which springs tend to urge it towards the shaft 1. The end of the cotter 5 which faces the shaft 1 can, at the time of each stoppage of the shaft 1, engage in either of two notches 4b in the ring 4, thus holding the cam 2 against rotation about the shaft 1.

The lateral control of the cotter at the time of each stoppage of the discontinuous rotary motion of the shaft 1 is ensured by means of two pivoting fingers 7 (FIG. 1). Each finger 7 is pivoted at 8 on the frame of the dobby, and the upper end of each finger 7 is pivoted to a common connecting rod 9, appropriately controlled by the customary reading device. The lower end of each finger 7 is bent back at right-angles in order to form a nose 7a of curved shape, said nose being engaged inside the outer groove 2b of the cam 2.

As shown in FIG. 3, a notch 5a is provided in the cotter 5. The notch 5a allows the noses 7a to pass during rotation of the cam 2. It will be understood that when the connecting rod 9 is displaced longitudinally in either direction, the fingers 7 pivot about their pin 8 such that the terminal nose 7a of the finger which is located opposite the cotter 5 abuts against one or the other of the transverse edges of the notch 5a, thus ensuring the lateral displacement of said cotter against the action of or under the effect of the springs 6.

A cradle 10, formed by two connected side plates which surround the lower part of said cam (FIGS. 6 and 7) is associated with each cam 2. The side plates of this cradle 10 are connected to each other by pins 11 which support two rollers 12 held in contact with the periphcry of the cam 2. The cradle 10 is suspended laterally from a connecting rod 13 pivoted at 14 to the frame of the dobby, and it is also supported by a second connecting rod 15a pivoted at 160 to the frame. The arrangement is such that the assembly formed by the cradle l and the connecting rods 13 and 15a constitutes a deformable parallelogram which allows said cradle to displace under the effect of the rotation of the cam 2, in an appropriate trajectory.

It will be noted that the connecting rod 15a is constituted by the upper extension of the customary pulling arm 15 which is connected, in known manner, to the heald frame or to the corresponding heald of the dobby.

In FIGS. 1 and 4, the nose 7a of the pivoting finger 7 located on the right-hand side is urged inwardly such that under the effect of the springs 6 the cotter is engaged in one of the notches 4b of the ring 4. The cam 2 is thus held against rotation with respect to the shaft 1, such that it is displaced with the latter by half a revolution, thus controlling the cradle and the arm 15.

After this half revolution, when the shaft 1 has stopped, the cotter 5 is controlled by the left-hand finger 7 in such manner as to be either held inside the notch 4b or, on the contrary, to be pulled radially outwards by the aforesaid finger. In the first case, the cam 2 remains held against rotation with respect to the shaft 1 and thus controls the cradle 10 and the arm by imparting a corresponding displacement to the heald frame associated with the latter. In the second case, the cam 2 (FIGS. 2 and 5) is dissociated from the shaft 1 and is kept angularly immobile by the fact that the nose 7a bears inside the aperture 2c. The cradle 10 and the arm 15 are consequently not controlled and remain immobile.

It will be understood that the cam 2 may have any shape capable of producing the exact movement desired for the pulling lever 15 (sudden or progressive displacement), which facilitates the precise adaptation of the dobby to the weaving envisaged. Each actuating member or relay comprises only a single bearing (the bearing 3); the latter has a reduced diameter and is subjected to only moderate stress which does not produce rapid wear and tear. The arrangement of the lower cradle 10 can be dismantled easily with a view to its maintenance or replacement, without this involving the complete dismantling of the dobby.

In the embodiment described in FIGS. 1 to 7, the dobby is of the positive type, the frames or healds being controlled on descending and ascending. However, it will be understood that the invention can be used with a view to producing negative dobbies in which the return of the frames is produced by springs or other elastic means. FIG. 8 diagrammatically illustrates the arrangement of an actuating member of such a negative dobby, the cradle 10 being replaced by a pivoting part or arm 16 provided with a roller 17 and attached to the pulling lever by a connecting rod 18. In this respect it will be noted that the majority of the parts necessary for producing a negative dobby of this type may also be used for positive dobbies. It will also be noted-that certain parts may be used for the construction of dobbies of the positive type (FIG. 9) or the negative type (FIG. 10'), which facilitates the economic construction of an entire series of looms. I claim:

1. In a dobby for looms of the kind comprising a number of actuating members which are interposed between a common reading device and pivoted pulling levers associated with looms healds and which are controlled by a common driving shaft rotated intermittently through successive advances of in synchronism with operation of the loom, and wherein each of said actuating memberscomprises a cam loosely carried by said common driving shaft and means under control of said common reading device to angularly connect said cam with said common driving shaft to raise and lower the corresponding one of said pivoted pulling levers, the improvement according to which said each actuating member comprises a cradle which partially surrounds said cam, two opposed rollers rotatably carried by said cradle to peripherically engage said cam, and a first and second connecting rod to support said cradle, said first connecting rod being positively connected with said corresponding one of said pivoted pulling levers.

2. In a dobby as claimed in claim 1, said corresponding one of said pivoted pulling levers being pivoted on a fixed pivot and said first connecting rod being in the form of an extension of said corresponding one of said pivoted levers.

3. In a dobby as claimed in claim 1, said means to angularly connect said cam with said common driving shaft comprising a controlling rod connected with said common reading device to be axially shifted in one and the other directions, and two pivoted fingers connected with said controlling rod on the side of said cam opposed to said cradle.

'4. In a dobby as claimed in claim 3, said cam having a radial aperture and a lateral groove which opens into said radial aperture, and said dobby further comprising groove and concentrically disposed with respect of same, while said connecting ring has a peripherically bent edge which is engaged into said additional groove, said opposed notches being cut into said peripherically bent edge. 

1. In a dobby for looms of the kind comprising a number of actuating members which are interposed between a common reading device and pivoted pulling levers associated with looms healds and which are controlled by a common driving shaft rotated intermittently through successive advances of 180* in synchronism with operation of the loom, and wherein each of said actuating members comprises a cam loosely carried by said common driving shaft and means under control of said common reading device to angularly connect said cam with said common driving shaft to raise and lower the corresponding one of said pivoted pulling levers, the improvement according to which said each actuating member comprises a cradle which partially surrounds said cam, two opposed rollers rotatably carried by said cradle to peripherically engage said cam, and a first and second connecting rod to support said cradle, said first connecting rod being positively connected with said corresponding one of said pivoted pulling levers.
 2. In a dobby as claimed in claim 1, said corresponding one of said pivoted pulling levers being pivoted on a fixed pivot and said first connecting rod being in the form of an extension of said corresponding one of said pivoted levers.
 3. In a dobby as claimed in claim 1, said means to angularly connect said cam with said common driving shaft comprising a controlling rod connected with said common reading device to be axially shifted in one and the other directions, and two pivoted fingers connected with said controlling rod on the side of said cam opposed to said cradle.
 4. In a dobby as claimed in claim 3, said cam having a radial aperture and a lateral groove which opens into said radial aperture, and said dobby further comprising a connecting ring driven by the said common driving shaft and having two diametrically opposed notches, an inwardly biased cotter slidably housed inside the said radial aperture and provided with a notch normally disposed in line with said lateral groove, while said two pivoted fingers have a bent end nose engaged into said lateral groove for shifting said inwardly biased cotter and engage same into one or the other of said opposed notches.
 5. In a dobby as claimed in claim 4, said cam having an additional groove outwardly exterior to said lateral groove and concentrically disposed with respect of same, while said connecting ring has a peripherically bent edge which is engaged into said additional groove, said opposed notches being cut into said peripherically bent edge. 